There is known a display unit for video of DVD (Digital Versatile Disk) to allow a user to easily enjoy video content not only at home but also in a vehicle. This video display unit, or video player is able to designate a mode for a caption or sound (speech language).
Non-Patent Document 1 describes a double-video display unit (called stereo display unit) as becoming popular; it can display different videos which can be respectively seen from different viewing positions (e.g., from a right-hand position or left-hand position). Furthermore, this double-video display unit allows sight lines from a driver seat and an assistant-driver seat to view mutually different videos, respectively, by adjusting viewable directions of the display unit.
Patent Document 1 describes a navigation device as allowing its display unit to be adjustable or variable in visibility and operability from either side position, i.e., right-hand position or left-hand position. Furthermore, Patent Document 2 describes a multi-screen display unit, in which a character output method can be changed with respect to each screen.
The double-video display unit in Non-Patent Document 1 is unable to designate a mode for a caption or sound with respect to each video. For instance, suppose that this device plays a video on two screen views for a child and a parent, and that the child wants to watch and listen to the video in Japanese dubbed from original English while the parent wants to watch and listen to the video in original English. In this case, the parent may reluctantly listen to the video in Japanese corresponding to the dubbing mode designated based on the child's preference.
The navigation device in Patent Document 1 does not disclose that two screens or screen views are simultaneously available. The multi-video display unit in Patent Document 2 needs to designate every character or every pattern in each view, so that it is not so easy for a user to designate characters and patterns in both views.                Non-Patent Document 1: ASCII24 News/topic, Apr. 20, 2005 “Display 2005 Report Vol. 3—Double-video display unit “Two different full-screened videos viewable from a driver seat and an assistant-driver seat, respectively”        <URL:http://ascii24.com/news/i/topi/article/2005/04/20/655512000.html?geta>        Patent Document 1: JP-2003-121160 A        Patent Document 2: JP-H02-297587 A        